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ABSTRACT

PRODUCTION OF USEFUL SHAPED ARTICLES, FORMED OF POROUS PLASTIC, BY EMULSIFYING DROPLETS OF AN AQUEOUS MEDIUM IN AN ORGANIC LIQUID CONTAINING POLYMERIZABLE ORGANIC COMPOUNDS(S) AND EMULSIFYING AGENT(S) AND, WITHOUT BREAKING THE DISPERSED NATURE OF THE EMULSION, POLYMERIZING IT UNTIL THE ORGANIC LIQUID HAS BEEN CONVERTED TO SOLID FORM. A RECESS INTO WHICH AT LEAST A PORTION OF THE OTHER MAY BE POSITIONED FOR NON-ROTATIONAL INGAGEMENT, SAID FIRST MEMBER DEFINING THE RECESS AND HAVING A PIVOTALLY MOUNTED LATCH MEMBER, THE SECOND MEMBER HAVING A PLANAR SURFACE, WHICH IN ENGAGED CONDITION IS PARALLEL TO THE PLANE OF SAID LATCH MEMBER, AND HAVING DEPENDING FROM THE PLANE THEREOF AT LEAST ONE ANGULARLY CONFIGURED TAB SELECTIVELY ENGAGEABLE WITH SAID LATCH MEMBER. IN ONE EMBODIMENT OF THE INVENTION, THE SAFETY MEANS IS PIVOTALLY MOUNTED ON ONE OF SAID MEMBERS TO PREVENT ACCIDENTAL MOVEMENT OF SAID PIVOTALLY MOUNTED LATCH MEMBER.

cited States Patent Other:

made by reissue.

ABSTRACT OF THE DISCLOSURE Production of useful shaped articles, formed ofporous plastic, by emulsifying droplets of an aqueous medium in an organic liquid containing palymeri'zable organic compoundsh) and emulsifying agenda) and, without breaking the dispersed nature of the emulsion, polymerizing l! mull the organic liquid has barn con verrert in solid form.

The present application is a continuation-impart of application Ser. No. 45,786, tiled July 28, i960, and en titled, Production of Cellular Materials From Vinyltype Resins," now abandoned.

This invention relates to a process for the production of porous plastics and the products produced thereby.

Several methods have been disclosed for the manufacture of porous plastic materials of sponge or foam-like structure. One known method, which is analogous to that used in powder metallurgy sintering, is merely to compact a powdered or granular polymer-at a temperature slightly below its melting point. In this 'way the particles are not fused intimately together but hollow spaces are left in the interstices of the mass.

According to another method, the powdered polymer is mixed with a granular soluble salt, for instance, a watersoluble salt and is heated until it is softened or molten to a compact mass. The soluble salt is then leached from the mass by 'a solvent, for instance, by water. The remalnlng product is porous. its density is dependent on the amount of soluble salt mixed with the polymer prior to heating the' same. It is also known to produce porous plastics by polymertzing a polymerizable compound and subjecting it either during or after its polymerization to the action of gases or of gasproducing compounds. This method suEers, among others, from the drawback that it can be applied but to a relatively small number of plastics, and that it does not allow one to regulate in a simple way the volume ratio of solid substance to pores, as well as the diameter of the individual pores.

It is the object of the present invention to provide a process for the productiomo'f'porous plastics which process is an improvement over said prior art process.

Another object of the present invention consists in providing a substantially stable composition containing a poiymeriza'olc monomer which composition, on subsequent polymerization, yields a porous plastic of improved prop- Cl'ilCS.

r object of the present invention consists in a porous polymer composition the pores of \l with a liquid material. .-.r object of the pnsent invention In to prouide an impr'n' :.l porous plastic of high strength properties.

Other objects of the present invention and advantageous A lur" Reissued July 18, 1972 features thereof will become apparent as the description proceeds.

In principle the objects of the present invention are achieved by providing a stable water-in-oil emulsion of the following composition:

(1) Water or an aqueous solution containing at least about [40] 25% water forming the dispersed phase: and

(2) A polymerizable organic liquid or a liquid the substantial portions or which consist of a polymerizable organic liquid which contains the following components:

(a) A polymerizable organic liquid consisting of a polymerizablc organic compound having a low molecular weight or of several organic compounds of a low molecular wegiht which are copolymerizabie with each other, said liquid being designated as constituent (a); and

(b) At least one organic compound of low molecular weight which is not copolymerimble with the constituent (a) and/or at least one organic compound of high molecular weight which is not copolymeriuole with the constituent (a) and/or at least one organic compound of high molecular weight which is copolymerizable with the con- 'stituent (a), said organic compound being soluble and contained in solution in the constituent (a) from which solution it is at least partly 'separated and precipitated at Ieatl Inthe plum boundary by the dlnpersed phase (1). whereby it acts as an emulsifier, llttld compound being designated as constituent (b).

(c) it required, at least one Ofgtttlit: compound of low molecular weight which is not copolymerlzable with the constituent (a) and/or at least one organic compound of high molecular weight which is not copolymerizable with the constitu nt (a) and/or at least one organic command of high molecular weight which is copolymerizable with the constituent (a) and which is soluble and contained in solution in the constituent (a), from which solution it is not separated and precipitated at the phase boundary by the dispersed phase (1), may be added. This compound, or compounds, is designated as constituent (c), all ol. said compounds (it), (b), and (c) forming the continuous phase. The thus composed emulsion is then polymerized in the presence of the usual polymerization initiators and activators to the porous polymer composition the pores of which, depending on the polymerization conditions, may still contain the aqueous liquid initially forming the dispersed phase (1) which [is finally] may be completely or partly eliminated from the thus obtained porous plastics.

In the porous plastics obtained in the atone-mentioned way, the pores are produced by the dispersed phase (I) and the structure of the plastic is produced by the continuous phase (2).

The fundamental discovery of the present invention is that it is possible to form water-in-oil emulsions in which the aqueous phase remains in its dispersed state even during and after the monomer is polymerized. These emulsions can be prepared by making use of microgels acting as the emulsifiers.

These microgels are believed to be peculiar to polymeric systems. When a polymer is dissolved in a solvent, and a non-solvent for said polymer is introduced into said solution, a turbid phase appears to precipitate out of solution. This turbid phase consists of finely divided droplets containing polymer, solvent, and non-solvent, and on further examination these droplets generally prove to be gelatinous. This formation of microgels is fundamentally different from a system which does not contain polymers. For instance, when sugar is in aqueous solution and a non-solvent for sugar is added, the sugar is precipitated in pure form, there being no turbid phase containing sugar, solvent, and non-solvent. For a more detailed explanation of the theory underlying the formation of rnfcrogcls. reference is made to the textbook, "Principles of Polymer Chemistry" by P. Jv Flory,

3 J Cornell University Press, Ithaca, New York, 1953, Chap- Vlll3 and XIII.

in the present inventionthe relationship between the .izent, non-solvent, and polymer or component (b) are extremely important. By varying these relationships, it is possible to produce either sponge-like materials hav- In intercommunicating pores or, on the other hand, foam-like material having isolated non-intercommunicating pores. Before proceeding with a discussion of these different possibilties, attention is directed to the following definitions of solvent, non-solvent, and polymer, as used in the present invention.

A solvent, or component (a) as defined hereinabove, is a liquid in which the polymer, or component (b) as defined hereinabove, is soluble at least to the extent of about 0.5 part, by weight, of the polymer in 100 parts, by weight, of solvent, preferably 2 parts of polymer in 100 parts of solvent.

A non-solvent, or dispersed phase (1) as defined hereinabove, is a liquid in which the polymer has a solubility of less than about 10.0 parts by weight, of polymer, preferably less than 1.0 part in 100 parts of non-solvent. Furthermore, the non-solvent should be soluble in the solvent in a range of about 0.00l part to 20 parts of non-solvent, preferably about 0.005-0.l part to 100 parts of solvent. (All of the solubilities as described above are those determined at room temperature or, if the monomer is a solid at room temperature, at 100' C.)

According to the process of the present invention porous plastics can be produced in which the volume ratio of solid matter to pores is approximately from 1:0.25 to 1:20 and in which the individual pores have a diameter approximately from 0.1;. to 60011. The volume ratio of solid matter to pores can be regulated in a simple manner by a corresponding selection of the ratio between the compounds forming the continuous phase (2) and the liquid forming the dispersed phase (1), while the diameter of the individual pores can be determined by producing a finer or coarser dispersion of the dispersed phase i) in the continuous phase (2).

The process according to the present invention for the production of porous plastics must not be confused with the conventional emulsion polymerization processes.

The latter processes are characterized in that an oil-inwater emulsion containing (a) water or an aqueous solution as the continuous phase (2),

(B) a polymerizable organic liquid or a liquid consisting substantially of a polymerizable organic liquid as the dispersed phase (1), and

(7) an emulsifier or a mixture of emulsifiers, respectively, and/or a protective colloid or a mixture of protective colloids, respectively,

is polymerized in the presence of polymerization initiators, and, if desired, in the presence of polymerization activators.

In said processes the plastic is obtained in the form of small, noncohesive, compact beads.

The emulsifiers which were used heretofore were soluble in at least one or both of the liquid phases and due to their chemica l properties are able to reduce the interiacial surfaceinsion between the water and oil phases. Although some of these emulsifiers can be satisfactorily utilized to form an emulsion of water-in-vlnyl-type monomcrs, it is well known that such emulsions will break on polymerization of the monomer. In other words, prior to the present invention, it was found that the dispersed water phase in a water-inwinyl-type monomer will coalesce before a solid polymerized structure is formed.

The water-in-oil-emulsions, which are useful in carrying out the process according to the present invention contain, as mentioned under (I). water or substantially ilifil' as agent forming lhe dispersed phase (l).

In general, the dispersed phase ii) is to contain [not less than 25] at least about 40% by weight, and preferably not less than 70%, by weight, of water.

In case the dispersed phase (1) does not exclusively consist of water, it contains, besides water, other additi es, which are soluble in water. Examples oi such added compounds are alcohols, in particular lower monohydric aliphatic alcohols like methanol, ethanol, 11- and iso-propanel, and n-, isoand tertiary butanol; furthermore lower organic acids like actic acid and propionic acid, moreover lower ethers and lowerketones like methyl ethyl ether and dimethylketone as well as inorganic salts like sodium chloride, potassium sulfate, sodium sulfate, magnesium sulfate, and magnesium chloride.

Organic liquids with a high dielectric constant like formamide and dimethylformamide, or saccharose, glucose, fructose, or other carbohydrates in aqueous solution may also be used as the dispersed phase (1).

As stated above, the water-in-oil emulsion forming the starting material for producing the porous plastic according to the present invention contains, as principal member of the continuous phase (2) described hereinabove, a polymerizable organic liquid or solvent designated hereinabove as component (a) which is a polymerizable organic liquid consisting of a polymerizable organic compound of low molecular weight or of several organic compounds of low molecular weight that are copolymerizable with each other. The continuous phase should in general contain not less than 10%, by weight, and preterably not less than 45%, by weight, of said constituent (a). It is also possible to use a solution of one or several non-liquid. copolymerlzable organic compounds of low molecular weight in one or several liquid copolymerlzable organic compounds at low molecular welglit. Cumpounds containing at least one group oi the formula and/or r s- 0 11:0 n

are particularly suitable as liquid polymerizable compounds of low molecular weight. Examplesthereof are compounds which contain, attached to an aromatic nucleus, vinyl or a-alkyl vinyl groups such as styrene, divinyl benzene, o, m-, pand a-methyl styrene, furthermore, esters and others of vinyl alcohol such as vinyl acetate, divinyl phthalate, divinyl maleate, vinyl butyl ether, divinyl ethanediol ether; additionally, acrylic and methacrylic acid esters such as ethyl acrylate, 1,2-propanediol diacrylate, methyl methacrylate, ethanediol dimethacrylate, butene-Z-diol-1,4-dimethacrylate, maleic acid diethyl ester; furthermore unsaturated hydrocarbon halides and cyanides such as vinylidene chloride, allyl chloride, chloroprene acrylonitriles, furthermore aliphatic hydrocarbons such as isoprene; as well as the esters and ethers of allyl and methallyl alcohols such as diallyl phthalate, methellyl methyl furnarate, l,2,3-tri(allyloxy) propane, diallyl diglycol carbonate, di-allylmalleate.

Suitable for being used as non-liquid polymerizable monomers of low molecular weight are gaseous and solid compounds, for instance, hutadiene, vinylchloride, vinyl naphthalene, vinyl carbazole.

The other essential constituent of the continuous phase (2) is the compound (b) which is, as stated above, at least one organic compound of low molecular weight that is not copolymerizable with the constituentta) and/or at lcast one organic compound of high molecular weigh which is or, respectively, is not copolymerizable with the constituent (a), whereby said constituent (b) must he soluble in the constituent (a) and must, at least partly, be separated and precipitated from said solution at the phase boundary by the constituent of the dispersed phase 1 l whereby it acts as an emulsifier.

'I'o find out whether a polymer can be user. as constituout lb}. the following simple small-scale test is carried out in the following manner. Either the prospective constituent lb). i.e., the polymer is added to water or the specific aqueous solution of the dispersed phase (I), i.e., the non-solvent whercafter the constituent (a), i.e., the polymerizablc monomeric solvent is admixed. Or the prospcctive constituent lb), i.e., the polymer is first dissolved in the constituent (a), i.e., the polymerizable monomeric solvent, whereafter water or the specific aqueous solution of the dispersed phase (1), i.e., the non-solvent is added. For instance, 1% to 2%, by weight, of the constituent (b) are dissolved in constituent (a) and a few drops of water or of the specific aqueous solution, are added to 10 cc. of said solution of constituent (b) to be tested in constituent (a). The mixture is shaken throughly and centrifuged at 2000 revolutions to 3000 revolutions per minute until phase separation takes place. Any compound is suitable for use of constituent (b) in combination with constituent (a) and the aqueous solution l) which produces in this test a turbid mixture of separation into separate phases. As a rule the more stable water-in-oil emulsions are obtained, the more pronounced is the separation or precipitation of the constituent lb) by the aqueous phase (1).

Suitable compounds (b) are in particular those which contain a major portion of hydrophobic groups and only a minor portion of hydrophilic groups. Such compounds are especially adapted to form the above mentioned microgcl. The particular type of mlcrogcl which is formed on addition of water or the above mentioned aqueous solution, i.e., the non-solvent (l) to the solution of solvent constituent (a) and polymer constituent (b) is not especially affected by the amount of non-solvent (1}. Larger amounts of non-solvent (l) merely result in larger amounts of water-in-oil emulsion. However, the polymerization is very considerably aficcted by the type of constituent (b) employed.

Suitable representatives of low molecular weight consttiuents (b) which are not copolymerizable with constituent (a) but are soluble therein and are precipitated from their solutions in constituent (a) by the addition of the aqueous solution (1) are emulsifiers as they are ordinarily employed for preparing watcr-in-oil emulsions, for i nstancc, esters of higher fatty acids with relatively low molecular polyhydric aliphatic alcohols, esters of higher fatty alcohols with lower and higher fatty acids, amides of higher fatty acids as well as salts of higher alkyl sulfonic acids.

However, the preferred and particularly suitable compounds for use as constituent (b) are polymerization products and polycondensation products which are not at all or only slightly soluble in water and which contain, as hydrophilic groups, carboxyl groups, carboxylate groups, carboxamide groups, hydroxyl groups, ester groups, ether groups, amino groups, ammonium groups, sulfonic acid groups, sulfonate groups, and/or sulfoxide groups.

Such non-copolymerizable compounds of high molecular weight are, for instance, copolymerization products having an acid number of about 8 to 12, of polymerizable carboxylic acids, such as acrylic acid, and hydrophobic polymerizable organic compounds, such as styrene, as well as copolymerization productsmf said type in which the curboxyl groups are partly or completely neutralized with organic or inorganic buses or are converted into carboxamide group by means of ammonia or amines. Polymcriration products and copolymerization products of styrcne, of methyl methncrylzue, and of vinyl acetate which are prepared by flllli\ll ll polymerization in the presence of persullutes and which, therefore, contain sulfonic acid or sulfonate groups, respectively, may be used. Furthermore, for instance, saturated polymerization products and saturated polycondcnsntion products which contain as hydrophilic groups. exclusively or practically exclusively cuter and/or other groups like polymethyl methacrylate and cellulose acetobuty rate may also be used.

Particularly suitable interpolymerizable compounds of high molecular weight arc, for instance, polycondensation products of the unsaturated polyester type containing carboxyl groups and/or hydroxyl groups and/or ether groups. Such unsaturated polyesters are composed of polyesters of polybasic, in particular dibasic, carboxylic acids and of polyhydric, in particular dihydric, alcohols. These unsaturated polyesters may also contain the radicats of monovalent carboxylic acids and/or the radicals of monovalent alcohols and/or the radicals of hydroxy carboxylic acids provided such unsaturated polyesters contain polymerizable ethylenically unsaturated groups. Such polyesters are described, for instance, in the book on Polyesters and Their Applications" by J. Bjorksten, H. Tovey, B. Barker and J. Henning, Reinhold Publishing Corporation, New York.

The polyesters can be prepared, for instance, from their components by a fusion-type condensation or a condensation under azeotropic conditions. Dihydric alcohols, for instance, ethanediol, 1,2-propanediol, 1,3-propanediol, diethylene glycol and l-allyl-2,3-hydroxypropanediol, in approximately stoichiometric quantities can be converted with u-ethylcnically unsaturated dicarboxylic acids such as maleic and turnaric acid, into polyesters suitable as constituent (b). Other unsaturated or saturated dicarboxyllc acids, like cndomethylcne tctrnhydrophthalic acid, tatt'tlhydrophthallc acid, 0-. mand p'phthnllc acid. succlnlcncld, and ldiplc acid, may IIIO be employed as condensation components of the unsaturated polyesters. Furthermore, mono-, tri-, or pulybusic citrboaylle llultls, such as propionlc acid, l,2,4-benzcnc. tricarboxyllc ucid, and l,2,4,5-bcnzenc tetrncarboxyllc acid and mono, nl-, or polyhydrlc alcohols, such as benzyl alcohol. l,2-di-lallyloxy)-3-propanol. Glycerol, and pc'ntaerythritol as well as hydroxy carboxylic acids, such as 4-hydroxy methyl cyciohexanc carboxylic acid can be used as additional components of the unsaturate polyesters.

Particularly stable emulsions are obtained with unsaturated polyesters in which the residual carboxylic groups are partly or completely neutralized with compounds having a basic reaction. Suitable compounds of basic reaction are, for instance, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, ammonia, amines such as ethylamine, triQB-hydroxy ethyl) amine, and a-methyl-fi-hydroxy ethylamine, furthermore water-soluble precondensation products of aminoplasts, such as precondensation products of formaldehyde and melamine, formaldehyde and urea, of formaldehyde and dicyandiamide. T has, to a water-in-oil emulsion containing a polymerizable organic liquid (0) and an unsaturated polyester obtained from unsaturated dicarboxylt'c acid and polyhydrlc alcohol as emulsifying agent (1;), one may add between about 0.01% and about 15% of the water-soluble preliminary condensation prodact of melamine and formaldehyde, calculated on the polymerizable organic liquid (a).

There may also be mentioned as copolymerizable compounds of high molecular weight polymerization products containing hydrophilic groups and, in addition, groups which can be further polymerized. Examples of such poiymeriztion products are prepolymerizatioa products from compounds containing hydrophilic groups as well as at least two polymerizable vinylidene groups, such as diallyl phthalate and ethylene glycol dimethacrylate, furthermore precopolyznerization products from compounds containing hydrophilic groups as well as at least two polymerizable vinylidene groups and compounds containing one polymerizable vinylidene group such as precopolymerization products from diullyl phthalate and ally] acetate or from ethylene glycol dimethacrylate and methyl methacrylate.

The efiiciency of the component (b) as an emulsifier is often increased by adding water-soluble organic compounds of low molecular weight containing a hydrophilic as well as a hydrophobic group additionally to the water forming the di perser. phase ll) oi the walcr-in-oil emulsion. Compounds which are suitable for this purpose are, in particular, IllCUllUlv. organic acids, others, and ketone its tit'ry arc mellliunc hcrcinabovc as agents forming the dispersel phase (ll. it is possible to readily find by means of the nbo c'mentioned small-scale test which agent forming the dispersed phase (1) is particularly suitable for being employed together with given agent (a) and (b) forming the continuous phase (2).

Suitable polymer constituents (b) of the continuous phase (2) have a minimum molecular weight of about 1,000. The preferred molecular weight range is between 20,000 and 200,000.

It has been found that the pH-value of the solventpolymer-non-solvent system is also of importance. For instance, to form a structure having non-intercornmunieating pores, it is necessary that the pH of the non-solvent aqueous solutions be higher than 5.0. An example of this system is: Polymethacrylate as the polymer, styrene as the solvent monomer, and a mixture of ethanol and water as the non-solvent. The microgel which consists of polymcthacrylate, styrene, ethanol, and water has an afiinity for the ethanol-water non-solvent mixture. This is due to the high concentration of polymethacrylate in the microgel and because said polymer contains ester linkages which are comparatively polar, thereby attracting the polar non'solvent. Similar systems are formed when the non-solvent contains water-soluble vinyl monomore such as acrylic acid, vinyl alcohol and acrylonitrile. These latter systems work especially well in the presence of water-soluble polymerization initiators.

in contrast to porous structures containing non-intercornmunicating cells, it is also possible to obtain what may be called a coherent system containing contiguous intcrcommunicating pores. This structure is when the microgel has a poor affinity for the non-solvent. For instance, when polystyrene prepared by emulsion polymerization and having a molecular weigh! of at least 10,000 is dissolved in methyl methacrylate, it is precipitated by small amounts of water. The microgel in this case contains a high proportion of polystyrene and therefore, it has a rather low afiinity for the nonsolvent water. When this system is polymerized with the aid of heat and a soluble peroxide, the water-in-ester emulsion undergoes a phase change at a certain stage of polymerization thereby resulting in a solid polymerization product having a three-dimensional framework, similar to a sponge, containing the non-solvent water throughout.

In these systems wherein water is utilized as the nonsolvent, the formation of a coherent mass is favored by pH values lower than 5.

Due to the complexities of the relationship between microgel and non-solvent, it is rather diflicultto predict in many cases whether the pores of the polymerization product will be communicating or non-communicating. In general, both types of pores are produced in the polymerization products obtained from water-in-oil emulsions according to the present invention, since a wide range of polarities can be imparted to all the materials used, i.e., the solventsor-eonstituent (a), the polymer or constituent (b), and non-solvent or agent forming the dispersed phase (1). In general, a foam-like, predominantly non-intercommunicating cell structure is obtained by taking care that the interfacial surface tension between the polymer solution in the solvent monomer and the non solvent is higher than the interfacial surface tension between the solvent monomer and the non-solvent alone. Likewise, if a predominantly coherent plastic is desired, the interfacial surface tension between the polymer solulion in the solvent monomer and the non-solvent is preferably lower than the intcrfacial tension between the solvent monomer and the non-solvent alone.

As stated het'cirtabuve, there may be added, if required, to the monomer constituent (a) and the emulsifying polymer constituent (b) a further constituent (c) obtained 1 which may be an organic compound of low molecular weight that is not copolymcrirabie with the constituent (a) and/or an organic compound of high molecular weight that is not copolymcrizzible with the constituent (a) and/or an organic compound of. high molecular weight that is copolymeriznble with the constituent (:1) provided said compounds are soluble in constituent (a) and are not separated or precipitated from said solution at the phase boundary by the agent forming the inner phase (1).

Suitable compounds of low molecular weight of the above mentioned type are, for instance, esters of lower alcohols with lower carboxylic acids or dicarboxylic acids, such as dibutyl phthalate and dimethyl adipate. Ifhese compounds can serve as plasticizers for the final porous plastics.

Suitable non-copolymerizable compounds of high molecular weight as mentioned above are in particular homo polymers and copolymers which are free of hydrophiiic groups as, for instance, bulk or precipitation polymers of styrene or vinylchloride, which has been prepared by using organic peroxides as polymerization initiators. Such polymers not only affect the properties of the final plastic such as its elasticity, hardness, and inflammability, but also the stability and other properties of the emulsion during its polymerization.

Other suitable copolymerizable substances of high molecular weight useful as constituents (c) are in particular homopolymerl and copolymcrl which are free of hydrophilic groups but still contain vlnyllilene fllulll 't. Examples of such substances are copolymerizution prodnets of styrene and butadiene. Such compounds are mtvantageously used to produce final products with particularly good electrical properties. The water-in-oil emulsions to be used in the process according to the present invention are preferably prepared in the following manner: The constituents (a), (b), and, it required, (c) forming the continuous phase (2) are mixed to form a solution whereupon the aqueous agent forming the dispersed phase (1) is slowly added to said solution while stirring and/or shaking so as to form an emulsion. Thereby, care must be taken that the resulting water-inoil emulsion is not converted into an oilin-water emulsion. In some cases it may be necessary to prepare the water-in-oil emulsion in another sequence of steps from its constituents. Thus it is possible first to mix the constituent (a) or the solvent of the continuous phase (2) with the aqueous agent or the non-solvent forming the dispersed phase (I) and thereafter to add the constituent (b) or the polymer or, if required, the constituents (b) and (c) of the continuous phase (2). Usually the emulsions according to the present invention are prepared under atmospheric pressure and at room temperature. However, if desired, it is also possible to operate at higher or lower pressure and/or at higher or lower temperature.

The water-in-oil emulsions according to the present invention contain the constituents forming the continuous phase (2) and the aqueous agent forming the dispersed phase (1) at a volume ratio of from about 1:0.25 to about 1:20, preferably at a volume ratio of from 1:1 to 1:10. The weight ratio of the constituent (a) or solvent of the continuous phase (2) to the constituent (b) or the polymer of the continuous phase (2) is an general between about 1:0.0002 and about 1:0.2, preferably be tween 1:0.0001 and 1:0.1. However, it may also be increased up to 1:4 if the constituent (b) is an organic substance of a high molecular weight. The weight ratio of the constituent (a) of the continuous phase (2) to the constituent (c) of the continuous phase (2) may range from l:0 to 1:3.8 provided the weight ratio of the con' stituent (a) to the sum of the constituents (b) and (c) does not become smaller than t :4.

In order to prepare porous plastics according to th present invention there-suiting watcr-in-oil emulsions arc polymerized. Polymerization may be initiated by admixin; wntsi ioluble as well as oil-soluble initiators, or initiators and activators, respectively, preferably at tempclxilurt-s lwtwcen about C. and about Hill C If initiitvns lltl activators are jointly used, it may be i iltllftllid Init lint: of these compounds he tyltictditlltll lc, \Vll lt'l\- llw other Hm: he soluble in oil. Stumble wnlurdllHll iniihdors or activators, respectively, are those which nrv usually employed in emulsion polymeriztu tinn snth us alkali formaldehyde sulfoxylzite, persul tales and hydrogen peroxide or, respectively, sodium hydrogen sulfite and cobalt chloride. Suitable oilsoluble initiators or activators, respectively, are also the conventional ones, such as benzoylperoxide, lauroyl peroxide, ethyl methyl ketone peroxide, cyclohexanone peroxide, and azo di-isobutyric acid nitrile, or, respectively, N,N-di-isopropyl-p-toluidine or other tertiary amines and cobalt naphthenate. The initiators and activatnrs are employed in quantities of from 0.1% to 10%, by weight, or, respectively, from 0.01% to by weight, preferably from 0.5% to 4%, by weight, or, respectively, 0.1% to 4%, by weight, calculated for the total weight of the emulsion. It may be of advantage for increasing the pot life" of the emulsion by dividing the same in two portions and adding the initiator to the one of said portions and the activator to the other one. Shortly before use the two portions are combined to yield the porous plastic.

1h: emulsion-i to which initiators or, respectively, llllllllltll'i and nclivntots have been added polymerize and harden depending upon their composition, the type and quantity of initiator or, respectively, of initiator and activator added, and the polymerization temperature, within a period of time ranging from a few minutes to several hours and yield porous plastics, the pores of which [118 filled with water, i.e., the aqueous dispersed phase l). The water diffuses in the course of time from the resulting porous structures or it is eliminated therefrom by a heat and/or pressure treatment. Although it could be expected that, on polymerization of the above-described water-in-oil emulsion, polymerization products are obtained which contain the aqueous medium or nonsolvent forming the dispersed phase (1) in the plastic structure in the form of fine droplets that are not interconnected with each other, the resulting porous plastics have also or ncrous pores which are interconnected with each other and are open at the surface of the plastic. This phenomenon is probably due to the fact that the water-in-oil emulsion becomes somewhat unstable during the course of the polymerization, so that the individual droplets of the dispersed phase cohere. This is in agreement with the fact that relatively unstable water-in-oil emulsions or emulsions which have been rendered unstable by the admixture of certain additives such as compounds of acid reaction or compounds forming compounds of acid reaction, respectively, for instance, ammonium chloride, sulfuryl chloride, and p-toluene sulfonyl chloride yield in the course of their polymerization, polymerization products with a pronounced coherence between the individual droplets of the aqueous agent forming the dispersed phase (1 J.

As has been found, the a mount of water added is of considerable importanctiin the production of a finely porous body on block polymerization of a water-in-oil emulsion according to the present invention. The amount of water required in order to produce a well-drying product can readily be determined by simple preliminary tests. In general said amount should not be less than 35%, by minute, of the total water-in-oil emulsion. Preferably .in-munts of water ranging from 45% to 95%, tug. at 11m: 5072, and more advantageously from 60% rOrr' than 66%, by volume, calculated for 1? emulsion are used for carrying out the process att-t rilmg to the present invention.

[)r3iz1g o the resulting porous polymerized body is consuls: :Wr improved by employing, as emulsifiers,

polymers of high molecular weight which are insoluble or hardly soluble in water, as this has been mentioned l'ltil'tiifltlbOVE in connection with the constituent lb). Such polymers are used in amounts between n/wu (Min and nlmu! 2.3%, nan! prt'frrnhly between alum! (I, m. (mi! about 1.2%, of the puiymerizablc portion ol tlw indium with the wtnern'n-nil emulsion cmimlnlng :1: [Will Sui; of said polymerlzable organic liquid (a).

The preparation of stable water-in-oil emulsions containing such large amounts of water results in the water being dispersed in the form of spherical droplets having a diameter between less than 1p. to approximately The spherical shape of the droplets yields cells of highly spherical form which impart to the final porous body an extremely high resistance to compression and which show when compared with foams of the same density obtained by blowing with gases or vapors, a compressive strength that is increased by more than 200%.

According to another embodiment of the present invention compounds capable of generating gases under the polymerization a'nd/or drying conditions, for instance, at increased temperature or decreased pressure may be added to the aqueous phase (1) or the continuous phase (2). Such gas generation may be caused by decomposition of said compound or by the transition of said compound from lhe dissolved or liquid state into the gaseous state. For instance, the aqueous phase (I) may contain compounds which readily split all carbon dioxide. or relatively rem-lily volatile, water-soluble lipophoblc cumnnnndu will 88 carbon dioxide. the constituents of the continuum phase (2) may contain, as blowing agent, relatively readily volatile, hydrophobic substances, for in lnuce, halogenated hydrocarbons, such as 1,l-dichloro-2,2-difiuoro ethane. The blowing emulsion in a coventiorial manner in the course of its preparation. The amount of blowing agent should not exceed about 20%, by weight, and should preferably be about 10%, by weight, of the total emulsion.

The water-in-oil emulsions as they are employed in the process according to the present invention may contain conventional additives as they are employed in the plastic art, for instance, plasticizers, dyes and pigmenm, organic and inorganic fillers, agents rendering the plastic thirtetropic, fireproofiing agents as well as inorganic or organic fibers, fabrics and woven textile materials. The process and products according to the invention can be applied for many products because, on the one hand, must of the known polymerizable monomeric organic compounds can be converted into plastics of known chemical composition and because, on the other hand, the properties of the porous plastics, due to the starting monomers and polymers used, are essentially the same as those of the corresponding non-porous plastics. Therefore, it is possible for a person skilled in the art to predict approximately which properties the individual porous plastics of known chemical composition will have. Hence, it is not difficult for a person skilled in the art to select suitable starting materials for the production of porous plastics of predetermined properties.

In order to produce porous plastic articles according to the process of the present invention, the Water-in-oil emulsion can be applied in the required thickness, for instance, to workpieces, materials, and tools of various types made from wood, metal, plastic, rubber, concrete, brickwork, or the like. Coatings may be produced therefrom or sheets, plates, webs or foils, if care is taken, for instance, by employing a mold release compound so tint the coating does not firmly adhere to the mold material. The coatings and plates and the like bodies are heat insulating and soundproof and, therefore, of particular importance, for instance, in the building art as flooring. wall and ceiling covering or facing or as supporting building material of light weight. The sheets and foils with tiller" communicating cells are useful, for instance, as breathing" artificial leather, i.e., leather permeable to air agent can be added to the insulin-z" picking material, i.e., packing material "Zliif to air, in particular, if libers, fabrics i t: t; 'i: mitcriul or organic materials are emon-ii E ii: piii'limlion ofsuch articles. The properties t l ti i il llf! :utilicinl leather can be diluted to those t l llli l' .l fdllil by adding hydrophilic tillers thereto. lnnlnul illvziincd according to the process of the present imcnti'm are also useful :15 cork substitute.

Furthermore, it is possible to use the watcr-in-oil emulsions according to the present invention as adhesives or to produce laminated bodies therefrom in which layers, for instance, from the above-mentioned materials, alternote with layers of porous t its plastic made from wateninoil emulsions. Shaped bodies of almost any shape, for instance, flat and corrugated plates, sheets, buttons, structural sections, door frames, pipes, casings, containers, shoe lasts can also be manufactured from such water-in oil emulsions according to techniques known per se in the manufacture of synthetic resins. Thereby, it is often advantageous to admix fibers and/or organic or inorganic, if desired, expanded filler materials such as mica, lava, pumice, and perlite. Thus, there can be obtained, depending upon the proportion of fibrous materials to emul sion, fibrous articles impregnated with plastics or articles reinforced with fibers, for instance, glass fibers. If filler materials are employed, their amounts added may be not only quite small, but also so large that they are the predominant component of the finished shaped article, for immune, light building lates and that therein the plastic tnlniltlfifiill. of the emulsion act! only as binding agent. lonely, porous filters [or gases and liquids as well a! semi riitors for storage batteries may also be produced by the process according to the present invention. The electrical resistance to the present invention. The inner electrical resistance of such separators is particularly low, if they are manufactured from emulsions containing inorganic salts dissolved in the aqueous agent forming the dispersed phase (1).

In place of fibrous materials such as glass fibers, or, respectively, in addition thereto, there may be embedded in the emulsion according to the present invention reinforcing elements such as metal screens, perforated rubber and plastic plates or sheets, and others.

The emulsions according to the present invention may be polymerized in suitable molds, for instance, by casting. In order to increase the rate of production of such cast articles, a solid polymer either in the form of a powder or in the form of a highly viscous solution, may be obtained prior to the polymerization of the emulsion, thereby increasing the rate of polymerization. Such polymer powders or solutions can be added prior to or subsequent to the emulsifying step. Preferred polymers are the polymerization product of the used monomers, for instance, polymethacrylate when using methacrylatc as constituent (a), polystyrene when using styrene as constituent (it), etc.

Thus, an emulsion according to the present invention which will polymerize very rapidly includes a solution of an activator such as a tertiary amine, an emulsifying polymer in a polymerizable monomer, a non-solvent which emulsitics with the latter two ingredients, and a solid polymer mixed with a suitable amount of an initiator such as lauroy'l'peroxide. Products made from a composition such as the one just mentioned will harden in a relatively short time when heated to a sufficiently high temperature. Furthermore, upon hardening, the mass will be readily separable from the mold due to the fact that water will act as a lubricant and mold release agent on the surface of the cast mass.

\(hen producing cellular plastic with predominantly non-lutercommunicating cells, it is possible to produce structural building materials wherein the cells are filled with dyestuffs or with agents protecting against ionizing radiat on. and the like. To prevent subsequent escaping and diiuslun of the cell contents from the cellular plastic iill 12 material, it may be provided with a protective coating scaling the cells.

Removal of the aqueous dispersed phase (1) after polymerization from the resulting orou plziltic is achieved, for instance. by drying at elevated temperature. in a vacuum, by compressing the plastic, or by allowing it to stand in an air current whereby the water cvnpor'ilc-l.

The resulting plastic articles may be rendered SUb'iiflll' tially fireproof by adding fireproofing agents such as chlorinated paraflins or water soluble salts such as ammonium carbonate thereto.

The hardened plastic articles may be coated, for instance, sprayed with lacquers or coated with metal or the like foils applied thereto by an adhesive.

As stated above, the resulting plastic material can he used for many purposes, for instance, for manufacturing advertising and packing material, toys and household goods, for interior decoration, shop windows, decoration for fair stalls, lamps, furniture, signboards or billboards, orthopedic devices, material for splinting bone fractures and others.

The following examples serve to illustrate the present invention without, however, limiting the same thereto.

Example 1 Two parts, by volume, of styrene containing 2% lauroyl peroxide as polymerization initiator, about 3% of polystyrene of a low intrinsic viscosity, and 0.3% of polyliinte are emulsified by stirring with one part, by volume, of a miners of 20% of ethanol and Start or water containing (till a of acetic Mill.

The resulting viscous water-inn" emulsion is printed in a mold wherein it is polymerized and hardened at Ft temperature of about 50 C. A solid porous mass, the pores of which are filled with water-ethanol is obtained. The liquid is subsequently evaporated from the pores by standing in air.

Example 2 One part, by volume, of methyl methacrylate containing 0.2% of polystyrene and 2.5% of methyl polymethacrylate is stirred with two parts of an aqueous solution of 0.55% of potassium persulfate, 0.1% of sodium sulfite, and 0.2% of acrylic acid which is adjusted to a pH between 8.0 and 9.0 by the addition of ammonia. The resulting water-in-oil emulsion is heated to a temperature between C. and C. for about half an hour and poured on a plate or in a mold which is also maintained at a temperature between 70 C. and 80 C. After half an hour to two hours, polymerization and hardening is completed and an opaque plastic sheet or molded article is obtained which contains water in finely dispersed mostly non-intercomrnunicating droplets.

Example 3 One part, by volume, of styrene containing 3% of polyvinyl acetate, 5% of dioctyl phthalate, and 1.5% of cumen peroxide is vigorously shaken with one part of a mixture of ethanol and water (2:1, by volume) which contains 0.05% of disodiurn saccharate and 0.01% of ferrous sulfate R50, and has a pH of about 9.0. The resulting water-in-oil emulsion is then heated to a temperature of 6070 C. while stirring. After the emulsion becomes thick and creamy, it is poured on a plate which is also held at a temperature of about 70 C. A plastic sheet is obtained containing mostly non-communicating droplets of the methanol-water mixture. It is blown up to a foam-like material by heating to a temperature above C.

Example 4 of a mixture containing 2 parts of acrylonitrile and 1 part of vinylidene chloride, which mixture contains 1% of polystyrene and L556 of polymethncrylate l3 emulsified by stirring with one part of water which contains l.5% of hydrogen peroxidz, 02

One part, by volume,

. 1'0 of glucose, 0.05% of ferrous sulfate, and 0.1% of sodium ethylene tlinninc tetra-acetate, said aqueous solution be- Example 9 iii" ul neutral reaction. Alter heating the mixture to I a mixture mmilmu Uf H g. of melhyl mama? .tu t rttntr- ,tiit'tlllf ctmlltltluthiy for about ten lmnutcs, hm and 20 g elhwmv "an"! mmcmucryhm M W- mull ji l ir m i i l: stituent (a) of the cmnpnnents forming the Cfllliillitmn i W Mace [m i 1 5 phase (2) there are diholvcd 1.8 g. of dinwlliyl p tolui Lurmi, Willlil cm itc transformed into a foam-line mutcriul l y slowly healing the same at a temperature above 170 C. for some time. When the volume of the plastic sheet does not increase any more, the resulting copolyrner is cooled rapidly to form a stable foam-like sheet.

Example 5 0.6 part, by weight, of styrene containing, in solution 2% of lauroyl peroxide and 2% of polystyrene and one part, by weight, of a water-ethanol mixture (3:1) are filled in an autoclave provided with a stirring device. Gaseous butadiene is then introduced until 0.4 part, by weight, thereof are absorbed. This mixture is then beated to 35 C, until the pressure decreases to about atmospheric pressure. The autoclave is then opened, and the resulting water-in-oil emulsion is filled in warm molds. After about half an hour, polymerization and hardening is completed. The molds are opened and the resulting orous copoiymcrs are dried in a warm air-stream.

Example 6 in 92.5 g. of methacrylic acid methyl ester as conatitucnt (a) of the compounds of the continuous phase (2) there are dissolved 5 g. of polystyrene produced by emulsion polymerization in the presence of peraulfatc as con stituent (b) of the components of the continuous phase (2) and 3.5 g. of a 50% benzoylperoxide paste. 1.7 g. of dimethyl-p-toluidine and 500 g. of water which forms the dispersed phase (1) are added to said solution while stirring vigorously The resulting water-in-oil emulsion is stirred at a temperature of 50 C. until a homogeneous [cast] casting mass is formed which is poured into molds and polymerized at a temperature of 50 C. Porous plastic articles are obtained containing water in finely dispersed form. The water can be eliminated on heating at a temperature of 60' C.

Example 1 In 100 cc. of styrene as constituent (a) of the components of the continuous phase (2) there are dissolved 2 g. of polystyrene produced by emulsion polymerization in the presence of persulratc as constituent (b) of the components of the continuous phase (2), 5 cc. of a 60% solution of methyl isobutyl ketone peroxide and 0.3 cc. of a solution of cobalt naphthenate. 60 cc. of said solution are added to 40 cc. of a mixture composed of 93 cc. of water and 7 cc. of isopropanol which mixture forms the dispersed phase (1). The mixture is stirred until a water-in-oil emulsion is formed. The emulsion is polymerized in a mold at a temperature between 70 C. and 90 C. A porous plastic article is obtained from which the components of the dispersed phase (1) can be eliminated by heating at a temperature between 60 C. and 70 C.

. Example 8 100 cc. of methyl metl' accy-Iate as constituent (a) of the components of the continuous phase (2) are added to 1.6 g. of dimethyl-p-toluidine and then mixed with 100 g. of polymethyl methacrylnte as constituent (b) of the components of the continuous phase (2) in which 2 g. f benzoylperoxide are finely dispersed. The mixture is stirred together uith 200 cc. of a mixture of 89 cc. of water and ll cc. of isopropanol which mixture forms the dispersed phase (ii until a watcr-in-oil emulsion is lormcd. The ctz'iul ion is then polymerized in a mold at a temperature between 40 C. and 50 C. for 10 minilt-s lo minutes. porous shaped body is obtained illllll uhicli the :cous dispersed phase can be expelled n. hun ing at art-nu ornture of 50" C.

dine and 2.5 g. of a copoiymcrizntion product of 25% of vinyl acetate and of methyl methacrylate producer. by emulsion polymerization in the presence of persulfate as a first portion of the constituent (b) of the components forming the continuous phase (2). The solution is vigorously stirred for 15-20 minutes together with g. of poly-methyl methacrylate as a second portion of said constituent (b) with the addition of 150 cc. of water as the component of the dispersed phase (1). After addition of 2 g. of benzoylperoxide dissolved in 15 cc. of ethyl methacrylate, the resulting water-in-oil emulsion is then applied to a glass fiber fleece which is impregnated therewith by enclosing it between two foils and pressing. Hardening is effected by heating at a temperature of 50 C. for 10 minutes to 15 minutes. A porous plastic plate reinforced by glass fibers is obtained thereby. The water contained therein is evaporated by heating at a temperature between 25' C. and 30 C. within about 24 hours.

\ Example 10 In atmlxture consisting of cc. of ltyrcne and 10 cc. of acrylonltrllc as constituent (a) n! the component's forming the continuous phase (2) there are tli nuivctl 5 cc. of a 60% solution of methyl isohulyl intone peroxide, 2 g. of polystyrene obtained by emulsion polymerization in the presence of pcrsuli'ate us a first portion of the constituent (b) of the components forming the continuous phase (2) and 1 cc. of a 10% solution of cobalt naphthenate. cc. of the resulting solution are mixed with 100 cc. of water as the component of the dispersed phase (1) while stirring, until a water-inoil emulsion is formed. 100 g. of polymethyl methacrylate as a second portion of said constituent (b) are added to said emulsion. The mixture is poured into a mold and polymerized at a temperature between 60" C. and 70 C. A molded body of a porous polymerimtion product is obtained from which the pore-forming water is evaporated by heating at a temperature of 20-25 C. for several hours.

Example 11 To a mixture consisting of 65 g. of an unsaturated polyester of the acid number 40 prepared from maleic acid, phthalic acid, and propylene glycol at a molar ratio of 2:1:3.3 as constituent (b) of the components forming the continuous phase (2) and 35 g. of styrene as constituent (a) of the components forming the continuous phase (2) there are added 2 g. of benzoylperoxide and, thereafter, slowly 100 cc. of water as component forming the dispersed phase (1). The mixture is vigorously stirred at a temperature of 10 C. until a water-in-oil emulsion is formed. The emulsion is mixed with 0.18 'g. of dimethyi-p-toluidine, poured on a glass plate to form a layer of the desired uniform thickness, for instance, be tween 1 mm. and 15 mm. and polymerized and hardened by heating at a temperature of 30' C. for 10 minutes. The water can be evaporated from the resulting porous plates by heating at a temperature between 80 C. and

Example 12 65 ,g. of the unsaturated polyester described in Exam pie 11 as a first portion of the constituent (b) of the components forming the continuous phase (2) as well as 1.5 g. of a copolymerizzttion product of the acid number 10 prepared from styrene and acrylic acid as a second portion of said constituent (b) are dissolved in 65 g. of

(a) A mixture of dialiyl phthaiate and styrene at a ratio of 1:3, by weight, or

(b) In 65 g. of allylchloride, or

mini.

, ll wlttna is minor trei on n. gloss pin ll layers of uniand polymerizttl and hardened at tern ai -70 (I. POIGXN nlttoiiri meats and plates ..-..n thereo Example H A liiflillyilll'llfillfin product of sirtlpy consistency as waturfnt (bl of the omponente arming the semina e if, its it is obtained from 7! g. of methyl mcth' l still contains monomeric methyl methncgtitoent {a} of the :ootponents forming the nose (2) is thoroughly [fillifld with 16.5 g. 1'55 glycol di-rnethylaorylate. 4.9 g. of a post: V 50% t bennoylpetoxide. and. 19.0 3. of. only it ide powder as constituent (o) oi the Qmp0- rn tg the continuum; phase. {2}. Tho mixture 7 n. my. loo of waior an oornponont forming the .pr; t l time: t until it water-En oll omulsion in in tj cumleiun i allowed lflfiltlfll-l some time if I u mamma of tlvumitllufl, Wltil'ifiifltfi' L 5!. Oldi lt'tilivi p tuluidmc an added. It in spread in the desired ti to... for imtnnro, of ,5 mm. to H) mm @1 10 fl'flifl it. the msuiting coating i'l polymerizcd it a tom-- 1"; to hit (I. for 10 minutes to minutes. Tilt: tot-red. to evaporate by standing at r: temporw Example 14 to a mixture containing of 65.) g. oi the unsaturated rint-oer rte-termed in Example 11 as constituent (b) of 2b. components form ng the continuous phase (2) and a of styrene condiment (a) of the componente rinirii'. tho continuous phaso (2.) there: are added 4.9 g. t 1 .i pintc containing 50% of henzoylperoxide as well it") of polyvinylchloride powder as constitucnt (c) components forming the continuous phase (2). :lting, mixturo is stirrod together with 150 g. of .3 component tanning rue diiperoed phase (1) until r-irroil emulsion is formed. After its Clo-aeration [ulXCLi with 30.0 g. 0% styrene and 8.8 g. of dimethyl rtuitiirte, poured into molds. and polymerized and .ed a: a temperature of C. A porous shaped is. obtained from whioh the water is eliminated by 1 to 100 C.

Examplr: 15

is prepared from 356 of styrene, 25.6 "nrerte tooth being tho conatrtnents (a) of the com.- the oontinuous phase {2), 60 g. of the d polyester described in Example [6] 1] to g, of benzoyl peroxide and 3.0 g. of triethanolaan. added to cause salt formation, said polyester salt 41;; the ronstituentlb) of the components forming the continuous phasfiTZ). The mixture is stirred @gether with I. of dmethybprtoluiciino and 83.0 g. of water as mm omen: forming the dispersed phase: {1) until ayaater idol e tltilsiC-n is iorrned. Said emulsion is. poured into will. and is polymerized and hardened at C. The miter is. eliminated from tho rewiring porous Shaped ..;:3 by heating at a lcmpcrututo of mil C.

Example 16 t p iflilt til iif, 11m! 500 g. o. prepolymetizution :tte n; ostitnent t u;

. mi iontinuotss :fl l t't'rf itlti with Til U g. (bl n1- l b 'll iirrf'iail who: (it until i z nc l the ewiring emotion ,wmw wing-remote at it. 1'. will t. who.

tho Witltif is eliminated gl l t the red bodies by hearing at 160" (H i Example 17 To 930 g. of methyl methacrylate as constituent (a) of the components forming the continuous phase (2) iters are added 5.0 g. of polystyrene produced by emulsion polymerization in the presence of per-sulfate. said polystyrene being the constituent (b) of the Components forming the continuous phase (2), 2.0 g. of benzoyl peroxide, 1.5 g. of dirncthyl-p-toluidine and 100.0 g. of a copotymcrization product powder as filler as it is obtainod irorn'fl parts of styrene and parts of the unsaturated polyester described in Example 11. The mixture is stirred with 150 g. of water as component forming the dispersod phase (1), until a water-in-oil entulsion. is formed. The emulsion is poured into molds and polymerized and. hardened atntemperatme of 50 C. water is eliminated from the obtained porous sheped Emilia by batting to C.

Hrnmpla lH Tl) g. of t i'ifljyij -tmiitlq til? tii1';i'l*- tl in ml g. ml n lmfiflltlmltll. t ulj owlcl ti". tlejttt s l ti jfi l ntllnpio ll tl l l .167 g. (if till/Forte. Gill] 1;. nf't mier lliL lowly nml g nil nally adder! to mill aoliitiun tel H) I. while dial-ills; until 21 white, unnmy walet' is': nil amui rml it [Uil hltl A solution at 6.8 g. of dltilntltyl fptoltliditlo in Hill g. of styrene isstirrod into said emulsion. The rcatlltng fluid emulsion is cast into plate molds in a zbieirncsst of about 5 mm. Die mold is exposed in a water bath to a torn perature of 50 C. The cast resin polyrnzrizes and hnrdens within about 10 minutes to 15 minutes. water is removed from the porous plastic ptates by beak ing to 100 C. The resulting plates have a density trfi.

Example 19 in place of styrene as usedin liirarnph ployed the some amount of methyl me. .358 n r. the other components, catalysts, emuls firing pros-adore, polymerization conditions, and removal oi the renter proceed in the same manner as described in said Example 18. A finely porous molded article of a density of 5.6 is obtained.

It may be mentioned that woteosolttble protective colloids and sorfaoe active agents must not b present in thoenrulsions because such protective colloids and snrfaeeactive agents would prevent formation of water'in oii emulsions to they are reqtrired in accordance t ttio the present invontion.

The amount of non-solvent or component forming the dispersed phase, i.e., of water or an aqueous liquid. is chosen sorthat it corresponds to the desired total pore volume and that permits' exact adjustment of said ore volume. Although the resulting porous plastic bodies are of considerable porosity. they still show smooth or bright snriaoes depending upon the mold walls.

The use of water as pore-forming component has considerable advantages. it prevents excessive overheating. even when the polymerization prooeeds strongly axothermically; especially when using rapid autivnrors. The polymorization heat: can be dissipated more readily. Thus it is possible to produce molded bodies of large size wit 1 out any excessive expansion of the polymeriration prod not. The olume of the resulting plasati hotl vnnes only slightly with respa zt to the starting volume uf the watenin-oil emulsion. Shrinkage i ind Alina-1, The molded bodies are readily released from no molds or 17 from surfaces on which they were cast due to the formation of a water film or of WillCl" vapors.

As stated above, the breathing: activity of plates, sheets, routines. foils made according to the present invention is excellent. The same l-i lrtu: wiil'l respect to their soundabsorbing and heat-insulating properties. The new plastics have very good elasticity properties and exhibit all the other working and processing advantages of plastics over other materials such as wood. Due to their fine porosity they can readily be drilled or nailed. They are especially valuable as leather substitute. The preferred leather substitute material is composed of the porous polymerization product of styrene or methyl methacrylate with an unsaturated polyester as constituent (b) of the continuous phase (2).

Of course, many changes and variations may be made in the composition of the various components of the vvater-inoil emulsions, in their polymerization, the removal of the dispersed phase (I) therefrom and the like in accordance with the principles set forth herein and in the claims annexed hereto.

I claim:

1. A method of producing solid materials having a plurality of droplets dispersed therein, which method comprises forming a stable water-in-oil emulsion composed of water, methyl-methucrylate, as the oil phase, and polystyrene having a molecular weight of at least 10.000 as the emulsifier, and polymerizing the methylzicrylatc to form polymethylmethacrylate without breaking the dispersed nature of the emulsion, thereby forming solid polymethylmethacrylate having a plurality of water droplets dispersed therein.

2. A method of producing solid materials having a plurality of droplets dispersed therein, which method comprises forming a stable watcr-in-oil emulsion composed of water, styrene, as the oil phase, and polystyrene, as the emulsifier; and polymerizing the styrene torform polystyrene without breaking the dispersed nature of the emulsion, thereby forming a solid plastic material having a plurality of water droplets dispersed therein.

3, A method of producing solid materials having a plurality of droplets dispersed therein, which method comprises forming a stable Watcr-in-oil emulsion composed of water, a mixture of styrene and acrylonitrile, as the oil phase, and polystyrene, as the emulsifier; and polymerizing the mixture of styrene and acrylonitrile to form a copolyrnerization product therefrom without breaking the dispersed nature of the emulsion, thereby forming a solid plastic material having a plurality of water droplets dispersed therein.

4. A method of producing solid materials having a plurality of droplets dispersed therein, which method oomprises forming a stable water-in-oil emulsion composed of water, styrene, as the oil phase, and an, unsaturated polyester obtained from maleic acid, phthalic acid, and propylene glycol, as the emulsifier; and polymerizing the styrene to form polystyrene without breaking the dispersed nature of the emulsion, thereby forming a solid plastic material having a plurality of water droplets dispcrsed therein.

5 A method of produc'uig solid materials having a plurality of droplets dispersed therein, which method comprises forming a stable water-in-oil emulsion composed of water, styrene, as the oil phase, an unsaturated polyester obtained from maleic acid, phthalic acid and p opylene glycol, as the emulsifier, and polyvinylchloride powder; and polymerizing the styrene to form polystyrene without breaking the dispersed nature of the emulsion, thereby forming a solid plastic material having a plurality oi uni :r droplets dispersed the ein.

6. A method of producing solid materials having a p urality of droplets dispersed therein, which method comprises forming a stable water-in-oil emulsion composed oi l I) an ziqmous medium selected from the group conand copolymen'zable mixtures thereof, said polymeriznble organic liquid forming the oil phase; and (b) a substantially water-insoluble polymeric compound being soluble in said polymerizable organic liquid, said compound being selected from the group consisting of substantially waterinsoluble polymerization products. [substantially water-insoluble polycondcnsation products, substantially water-insoluble unsaturated polyesters obtained from unsaturated polycarbottylic acids and polyhydric alcohols] and mixtures thereof, said polymeric compounds con taining hydrophilic groups in an amount insufficient to essentially increase their solubility in. water, said polymeric compound forming the emulsifying agent on contact with said aqueous medium; and polymerizing the polymerizable organic liquid in said watcr-in-oil emulsion to form the respective polymerization product without breaking the dispersed nature of the emulsion, thereby forming a solid plastic material having a plurality of water droplets dispersed therein.

7. A process for'thc production of porous plastics, which process comprises forming a stable water-in-oil emulsion containing (1) an aqueous medium selected from the group consisting of water and an aqueous solution, said aque' ous medium being the agent forming the dispersed phase, said aqueous solution containing at least about 25%, by weight, of water, and

(2) as dispersion medium, an organic liquid contain- (a) a polymerizable organic liquid selected from the group consisting of a 'polymerizable organic compound and at least two such organic compounds being co-polymerizable with each other;

(b) at least one organic compound being copolymcrizable with said polymerizable organic liquid (a), said organic compound being soluble in and being contained in solution by said polymcrizablc organic liquid in) and being at least partly separated from said solution at the phase boundary by addition thereto of said aqueous medium (1), thereby acting as an emulsifier; and

(c) at least another organic compound being soluble in and contained in solution by said polymerizable organic liquid (a) and not being separated from said solution at the phase boundary by the addition of said aqueous medium (I), said organic liquid (2) forming the continuous phase,

polymerizing said water-in-oil emulsion in the presence 19 of cunyentionul poly-mediation initiators as well as conventional polymerization uctiuutors without breaking the water-in oil emulsion, and, at least partly, removing the aqueous medium (it from the resulting porous plastic.

8, 'llw [JltlL'tfiv :icutllltl'li'. lU claim 7, Wi'ltl'lilll the IL suiting water iu-oil CllllllniOi'lcontains at least 50%, by volume, of water.

9. The process according to claim 7, wherein the re sulting water-in-oil emulsion contains more than 66%, by volume, of water.

10. The process according to claim 7, wherein the aqueous medium is an aqueous solution of an inorganic salt.

ll. The process according to claim 7, wherein the spherical droplets of water contained in the resulting water-in-oil emulsion have a diameter not exceeding 50 12. The process according to claim 7, wherein the polymerizable organic liquid (a) is a. compound selected from the group consisting of styrene, an acrylic acid ester, a methacrylic acid ester, and a mixture thereof.

13. The process according to claim 7, wherein the organic compound (b) is an unsaturated polyester, the free carboxyl groups of which are at least partly neutralized by a compound of basic reaction.

14. The process according to claim 7, wherein fillers, fibrous materials, and reinforcing agents are added to the water-in-oil emulsion.

15. The process according to claim '7, wherein between 0.01% and about calculated for the polymerlzable organic liquid (in), of the water soluble preliminary coutlcnsation product of melamine and formaldehyde are added to the water-in-oil emulsion containing a polymerizable vinyl compound as polymerizable organic liquid (a) and an unsaturated polyester obtained from an unsaturated dicarboxylic acid and a polyhydrie alcohol as emulsifying agent (b), said unsaturated polyester being soluble in and dissolved by said polymerizable vinyl compound.

16. The process according to claim 7, wherein between about [0.05%] 0.1% and about 2.5%, calculated for the polymerizable portion of the water-incl] emulsion of the emulsifying agent (b) consisting of a polymerizatiort product of high molecular weight being soluble in the water-insoluble polymerizable ethylenieally unsaturated organic liquid (21), and at least 50% of said polymerizable organic liquid (a) are present in said waterin-oil emulsion.

17. The process according to claim 16, wherein between about 0.3% and about 1.2%, calculated for the polymerizable portion of the water-in-oil emulsion of the emulsifying agent (b) consisting of a polymerization product of high molecular weight being soluble in the water-insoluble polymerizable ethylenically unsaturated organic liquid (at), and at least 50% of said polymerizable organic liquid (a) are present in said water-in-oil emulsion.

IS. The porous plastic produced by the process of claim 7.

19. A method of producing porous plastic shaped products, whichmethod comprises forming a stable water-inoil emulsion composed of water, methylrnethacrylate, as the oil phase, and polystyrene having a molecular weight of at least l0,000 as the emulsifier, shaping the emulsion to the desired product, polymerizing the methylmethacrylale to form polymethylmethacrylate without breaking the dispersed nature of the emulsion, thereby forming the solid shaped polymethylmethacrylate product having a plurality of water droplets dispersed therein, and at least partly removing the water from the resulting product.

20. A method of producing porous plastic shaped products which method comprises forming a stable water-inoil emulsion composed of water, styrene as the oil phase and polystyrene as the emulsifier, shaping the emulsion it) the desired product, polymerizing the styrene to form polystyrene without breaking the dispersed nature of the emulsion, thereby forming the solid shaped plastic product having a plurality of water droplets dispersed therein, and at least partly removing the Willfil' from the resultlug product.

21. A method of producing porous plastic shaped prod acts, which method comprises Forming a stable water-inoil emulsion composed of water, a mixture of styrene and acrylonitrile as the oil phase, and polystyrene as the emulsifier, shaping the emulsion to the desired product, polymerizing the mixture of styrene and acrylonitrile to form a copolymerization product therefrom without breaking the dispersed nature of the emulsion, thereby forming the solid shaped plastic product having a plurality of water droplets dispersed therein, and at least partly removing the water from the resulting product.

22. A method of producing porous plastic shaped products, which method comprises forming a stable water-inoil emulsion composed of water, styrene as the oil phase, and an unsaturated polyester obtained from maleic acid, phthalic acid, and propylene glycol as the emulsifier, shap ing the emulsion to the desired product polymerizing the styrene to form polystyrene without breaking the dispersed nature of the emulsion, thereby forming the solid shaped plastic product having a plurality of water droplets dispersed therein, and at least partly removing the water from the resulting product.

23. A method of producing porous plastic shaped products. which method comprises forming a stable water-inoil emulsion composed of water. styrene at the oil phase. an unsaturated polyester obtained from mulelc llClll, phthttllc ncld. and propylene glycol M the emulsll'ler, and polyvlnylchloride powder, shaping the emulsion to the desired product, polymerizing the styrene to form poly styrene without breaking the dispersed nature of the emulsion, thereby forming the solid shaped plastic product having a plurality of water droplets dispersed therein, and at least partly removing the water from the resulting product.

24. A method of producing porous plastic shaped products, which method comprises forming a stable waterin-oil emulsion composed of (1) an aqueous medium forming the aqueous dispersed phase and (2) as dispersion medium, an organic liquid containing (a) a polymerizable organic liquid forming the oil phase and (b) an emulsifying agent, shaping the emulsion to the desired product, polymerizing the polymerizable organic liquid in said water-molt emulsion to form the respective polymerization product without breaking the dispersed nature of the emulsion, thereby forming the solid shaped plastic product having a plurality of water droplets dispersed therein, and at least partly removing the water from the resulting product.

25. A method of producing porous plastic shaped products, which method comprises forming a stable water-inoil emulsion composed of (I) an aqueous medium forming the aqueous dispersed phase and (2) as dispersion medium, an organic liquid containing (a) a polymerizable organic liquid forming the oil phase and (b) an emulsifying agent,

the water content of said water-in-oil emulsion being between about 25% and about shaping the emulsion to the desired product, polymerizing the polymerizable organic liquid in said water-in-oil emulsion to form the respective polymerization product without breaking the dispersed nature of the emulsion, thereby forming the solid shaped plastic product having a plurality of water 21 vlmplcts dispersed therein, and at least partly removing water from the resulting product.

26. The porous plastic shaped product produced by the ocess} method of claim 24.

37. A method in accordance with claim 2d wherein suit emulsifying agent (b) includes an unsaturated polycstt'r, the free carboxyl groups of which have at least pa tly been converted to salts.

23. A method in accordance with claim 24 wherein said emulsion contains reinforcing fibers.

29. A method in accordance with claim 24 wherein said emulsion is shaped in a mold having the shape of a useful object and polymerized therein.

30. A method in accordance with claim 24 wherein said aqueous medium is present in said emulsion in the form of droplets having a diameter not exceeding 50 31. A method in accordance with claim 24 wherein said dispersion medium includes a water-insoluble organic compound having more than one polymerizable ethyleuically unsaturated group.

32. A method in accordance with claim 24 wherein said emulsifying agent includes a polymeric compound which has hydrophilic groups and will form a turbid phase or precipitate when a solution of said compound in said dispersion medium is contacted with said aqueous medium, the amount of said hydrophilic group being insuflicient to increase the solubility of said polymeric compounds to the extent that they become essentially soluble in water.

33. A method in accordance with claim 24 wherein said aqueous phase is a solution of ethanol in water, said emulsifying agent (b) is polystyrene, said polymerization is continued until the water-in-oil emulsion ls hardened to a solid shaped plastic product having a plurality of droplets of said solution dispersed therein in contiguous interconzmunicating pores, and at least part of the solution is removed by exposing said product to air at room temperature.

34. A method of producing solid materials having a plurality of droplets dispersed therein, which method comprises forming a stable water-in-oil emulsion com posed of (I) an aqueous medium selected from the group consisting of water and aqueous solutions of watersoluble alcohols, lower organic acids, lower alkanones, alkali metal salts, and magnesium salts said aqueous medium forming the aqueous dispersed phase, said aqueous solutions containing at least about 40% by weight, of water, (2) as dispersion medium, on organic liquid containing (a) a polymerizable organic liquid seleced from the group consisting of a polymerizable compound having at least one ethylenically unsaturated group and copolymerizable mixtures thereof, said polymerizable organic liquid fortning the oil phase; and a substantially water-insoluble polymeric compound being soluble in said polymerizable organic liqllid, said compound being selected from the group consisting of substantially water insoluble polymerization products, and mixtures thereof, said polymeric compou/uls containing hydrophilic groups in an amount iusufi'icient to essentially increase their solubility in water, said polymeric compound forming the emulsifying agent on contact with said aqueous medium: mu! -{wwriging the polwnerizable organic liqnii in said htlltF-l't-Ull emulsion to form the respective polymertzatt'on prom-ct without breaking the dispersed nature of the mttulsm t. thereby forming a solid plastic mat rial having u plur titty of water droplets disperser! therein.

35. A method in accordance with claim 34 wherein said ta-trulnfx'ing agent (it) includes an unsaturated poly- 22 ester, the free carboxyl groups of which have at least part1 y been converted to salts.

36. A method in accordance with claim 34 hltef-Z'ln said emulsion contains reinforcing fibers.

37. A method in accordance with claim 34 wherein said emulsion is shaped in a mold having the shape of a useful object and polymerized therein.

'38. A method in accordance with claim 34 wherein said aqueous medium is present in said emulsion in the form of droplets having a diameter not exceeding 50p.-

39. A method in accordance with claim 34 wherein said dispersion medium includes a water-insoluble organic compound t: ving more than one polymerizable ethylenically unsaturated group.

40. A method of producing solid materials having a plurality of droplets dispersed therein, which method comprises forming a stable water-in-oil emulsion composed of (I) an aqueous solution of water-soluble magnesium salt forming the aqueous dispersed phase, said aqueous solution containing at least about 40% by weight, of water,

\ (2? as dispersion medium, an organic liquid contain- "{a) pol ymert'zable organic liquid selected from t the group consisting of a polymerizable compound having at least one ethylenically unsaturated group and copolymertzablc mixtures thereof, said polymerizable organic liquid forming the oil phase; and

(b) substantially water-Insoluble polymeric compound being soluble in said poly/heritable organic liquid, said compound being selected from the group consisting of substantially water-[tn soluble polymerization products, and mixtures thereof, said polymeric compounds containing hydrophilic groups in an amount insufficient to essentially increase their solubility in water, said polymeric compound forming an emulsifying agent on contact with said solution:

and polymerizing the polymerlzable organic liquid in said water-in-oil emulsion to form the respective polymerization product without breaking the dispersed nature of the emulsion, thereby forming a solid plastic material having plurality of water droplets dispersed therein.

41. A method of producing solid materials having a plurality of droplets dispersed therein, which method comprises forming a stable water-in-oil emulsion composed of (I) an aqueous solution of water-soluble alkali metal salt forming the aqueous dispersed phase, said aqueous solution containing at least about 40% by weight, of water (2) as dispersion medium, an organic liquid containing (a) polymerizable organic liquid selected from the group consisting of a polymerizahle compound having at least one ethylenically unsaturated group and copolymert'ze mixtures thereof, said pol mertzable organic liquid formin the oil phase: and

(b) substantially water-insoluble polymeric compound being soluble in said polymerizahle organic liquid, said compound being selected from the group consisting of substantially water-insoluble polymerization products, and mixtures thereof. said polymeric compounds containing hydrophilic groups in an amount insufft'iwtt to essentially increase their solubility in water, said polymeric compound forming an emulsifying agent on contact with said solution:

and polymerizing the polymerizable organ lc liquid in said water-in-0il emulsion to form the respective yu lytneriattion product without breaking the dispersed nurnn the 23 t sion, tln'rchy forming a solid plastic material having a t trdllw of water droplets disperser! therein.

L. ,1 method (1] producing solid materials having a of droplets dispersed therein, which method il s forming a stable wutcrin-oil emulsion cotnit an aqueous solution of 1lttl'.'l'-\'0llll)l lower alht'ttmte forming the aqueous dispersed phase, said aqueous solution containing at least about 40% by weight, water,

31 as dispersion medium, an organic liquid containtag (a) polytnerlzable organic liquid selected from the group consisting of a polymerizable compound having at least one cthylenically unsaturated group and copolymerizable mixtures thereof, said polymerizable organic liquid forming the oil phase; and

(b) substantially water-insoluble polymeric compound being soluble in said polymerizable organic liquid, said compound being selected from the group consisting of substantially water-insoluble polymerization products, and mixtures thereof, said polymeric compounds containing hydropht'lic groups in an amount insufficient to essentially increase their solubility in water, said polymeric compound forming an emulsifying agent on contact with said solution;

and pol merizing the polymerizable organic liquid in said wuter-imoil emulsion to form the respective polymeriza llttrt product without breaking the dispersed nature of the emulsion, thereby [arming a solid plastic matrrlul having a plurality of water droplets dispersed therein.

43. A rrtctltotl of producing solid materials having a plurality of droplets dispersed therein, which method comprises forming a stable water-ln-oll emulsion composed of (I) an aqueous solution of water-soluble lower organic acid forming the aqueous dispersed phase, said aqueous solution containing at least about 40% by weight, of water,

(31 as dispersion medium, an organic liquid containing (a) p0l \'IllerlZflbl8 organic liquid selected from the group consisting of a polymerizable compound having at least one ethylcnically unsaturated group and copolymerizaltle mixtures thereof, said polynterizable organic liquid forming the oil phase; and

(b) substantially water-insoluble polymeric compound being soluble in said polymerizable organic liquid, said compound being selected from the group consisting of substantially water-insoluble polymerization products, and mixtures thereof, said polymeric compounds containing hydrophilic groups in an amount insuflicient to essentially increase their solubility in water, said polymeric compound forming an emulsifying agent on contact with said solution;

and polymerizing the polymerizeable organic liquid in said wttter-t'rz-oil emulsion to form the respective polymerigution product without breaking the dispersed nature of the emulsion, thereby forming a solid plastic material having a plurality of water droplets dispersed therein.

44. A method of producing solid materials having a plurality of droplets dispersed therein, which method comprises forming a stable water-in-oil emulsion composed 0) ll) an aqueous solution of water-soluble alcohols jorming the aqueous dispersed phase, said aqueous solution containing at least al=out 40% by weight, of water,

131 as tlistwrslt 't ltltllllttll, an rganic liquid containin! pu uttctt'nthle viper-tilt liquid selected from 24 the group consisting of a polymerizable compound having at least one cthyleuically unsaturated group and copolymerisahle mixtures thereof, said polymerizable organic liquid forming the oil phase; and (b) substantially water-insoluble polymeric cornpound being soluble in said polymerizable orgaulc liquid, said compound being selected from the group consisting of substantially waterinsoluble polymerization products, and mixtures thereof, said polymeric compounds containing hydrophilic groups in an amount lnsuflict'ent to essentially increase their solubility in water, said polymeric compound forming an emulsifying agent on contact with said solution; and polymerizing the polymerizable organic liquid in said water-in-ot'l emulsion to form the respective polymerization product without breaking the dispersed nature of the emulsion, thereby forming a solid plastic material having a plurality of water droplets dispersed therein.

45. A method of producing solid materials having a plurality of droplets dispersed therein, which method comprises forming a stable water-in-oil emulsion composed f (I) water forming the aqueous dispersed phase;

(2) as dispersion medium, an organic liquid containtag (a) polymerizable organic liquid selected from the group consisting of a polymerizable compound having at least one ethylenlcally unsaturatetl group and copolymertzahle mt'rtttres thereof, said polymer/table organic liquid tarmlag the all phase,- and (it) substantially water insoluble polymeric ctmtpound being soluble in said polymertzable organic liquid, said compound being selected from the group consisting of substantially waterinsoluble polymerization products, and mixtures thereof, said polymeric compounds containing hydrophilic groups in an amount insufl'icient to essentially increase their solubility in water, said polymeric compound forming an emulsifying agent on contact with said water; and polymerizing the polymerizable organic liquid in said water-in-oil emulsion to form the respective polymerization product without breaking the dispersed nature of the emulsion, thereby forming a solid plastic material having a plurality of water droplets dispersed therein.

46. The process according to claim 7 wherein said aqueous solution contains at least about by weight, of water.

References Cited The following references, cited by the Examiner, are of record in the patented file of this patent or the original patent.

UNITED STATES PATENTS 2,473,801 6/1949 Kropa. 2,505,353 4/1950 Fisk. 2,726,177 12/ 1955 Law. 2,739,909 3/ 1956 Rosenthal. 2,843,556 7/ 1958 Moorman. 1,967,220 7/ 1934 Barret et 211. 2,016,199 10/1935 Howard. 2,112,529 3/ 1938 Haze. 2,120,935 6/ 1938 Groff. 2,220,685 11/1940 Myers. 2,327,968 8/ 1943 Ripper. 2,443,735 6/ 1948 Kropa. 2,533,270 12/ 1950 Linkletter. 2,655,496 10/ 1953 Adams. 2,864,777 12/ 1958 Grecnhoc. 2,912,399 11/1959 Bartl.

(Additional references on following page) UNITED STATES PA'ITENI OFFICE CERTIFICATE OF CORRECTION Patent No. Re 7, 444 Dated uly 1 1972 Invent r( Guenther Will It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Calumn 1, line 10, after "W26093" please insert 7 application in Portugal, August 1.7, 1962, No. 39,953.

Column 1, line 23, please cancel "pounds (s) and substitute pound(s) Column 3, line 2, please cancel "ers" and substitute ters Column 4, line 10, please separate lowerketones" into the two words lower and ketones Column 5, line 20, please cancel "of" and substitute Column 6, line 37, please cancel "unsaturate" and substitute unsaturated line 61, please correct the spelling of "polymerization" Column 7, line 8, please make "agent" plural.

Column 8, line 21, please cancel "has" and substitute have line 63, please cancel "an" and substitute in Column 10, line 35, please correct the spelling of "conventional" line 44, pleas correct the spelling of "fireproofing" Patent No. Re 27,444 Dated July 18, 1972 Inventor(s) Guenther Will Page 2 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Lolumn ll, lines 33 and 34, please cancel "The electrical resistance to the present invention. 7 line 53, please make "product" plural.

Column 12, line 57, please correct the spelling of "cumene".

Column 18, line 73, please place the expression said organic liquid (2) forming the continuous phase," on a line or lir es separate from um (l) having the same margins as subparagraphs (l) and (2) appearing at lines 47 53 of column 18.

Column 21, line 26, please make "group" plural.

Column 22, line 59, please correct the spelling of "copolymerizable" column 23, line 60, please correct the spelling of "polymerizable" Signed and sealed this 26th day of March 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents 0PM F S-105G {10-53: USCOMM DC 60376 was: 

